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Reducing wastewater's environmental impact
Monitoring helps us know if waterway health is changing, and if our wastewater operations are having an impact on the aquatic environment. It can show us if water quality could affect plants or animals, or the health of people who use waterways for swimming and recreation.
Our aquatic monitoring programs
We conduct detailed long-term aquatic monitoring programs. These help identify long-term trends in water quality and waterway health, monitor our performance and understand how wastewater interacts with the environment.
The Sydney Water Aquatic Monitoring (SWAM) program began in July 2023. SWAM replaced the Sewage Treatment System Impact Monitoring Program (STSIMP), which ran from July 2008 to June 2023.
We've documented an understanding of how wastewater overflows interact with the environment under wet-weather conditions in our Wet Weather Overflow Monitoring Program 2016 to 2024 synthesis report. We've summarised the key points in the video.
Aquatic monitoring interpretive reports
We now produce aquatic monitoring interpretative reports every 4 years to provide in-depth analysis of trends in waterway health.
| Report title | What it's about |
|---|---|
STSIMP 2019–20 interpretive report: |
The report focuses on comprehensive statistical analysis and interpretation of nutrient loads data for all our inland wastewater treatment plants (WWTPs) and receiving water quality data for the Hawkesbury-Nepean River and tributaries. |
We conduct long-term monitoring of ocean sediments to see if there's any impact from our deep ocean outfalls at Malabar, Bondi and North Head. Detailed analysis of the data is reported in the 4-yearly Ocean Sediment Program report. |
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STSIMP 2016–17 interpretive report: Trends in wastewater treatment plant nutrient loads and water quality of the Hawkesbury-Nepean River |
The report analyses and assesses both the long-term (1992–2017) and short-term (post major upgrade) WWTP nutrient loads and receiving water quality trends in the Hawkesbury-Nepean catchment. It also explores factors driving change in concentrations of nutrients, chlorophyll-a and algae in the river and its tributaries. |
STSIMP 2013–14 interpretive report: |
The report uses long-term trend analysis (greater than 10 years) to identify significant changes in the environmental performance of the wastewater system and receiving waters. It also incorporates individual case studies, the annual data report and detailed assessment of marine benthic and sediment quality (Ocean Sediment Program). |
Yearly aquatic monitoring data reports
We produce yearly data reports to provide a check on environmental impacts. They include a summary of how our water resource recovery facilities are performing. Our most recent data reports are:
If you'd like to see past data reports, email epareports@sydneywater.com.au.
Temporary Penrith to St Marys flow diversion
We're working to safely stabilise the banks of Boundary Creek, which is downstream from our Penrith Water Resource Recovery Facility. To do this, we need to send some of the treated wastewater from the Penrith facility to our St Marys Water Resource Recovery Facility. As a result, more treated wastewater from the St Marys facility will go into Unnamed Creek, a tributary of South Creek. To understand any potential impacts to the waterway, we're closely monitoring its health before, while and after the work is done.
Our Environment Protection Licences for the St Marys and Penrith facilities have been updated to show this change.
We'll regularly update our monitoring results in line with our monitoring plan and licence requirements. View the latest results in the 2024–25 St Marys Water Resource Recovery Facility monitoring report. You can also view the state of the environment report for the baseline monitoring period.
Monitoring wastewater at our facilities
We monitor the quality of our treated wastewater before it leaves our water resource recovery facilities.
Each wastewater system has an environment protection licence set by the NSW Environment Protection Authority (EPA) for its network of pipes and the water resource recovery facility that treats the wastewater. Licences specify the performance standards we must meet and the monitoring we must do.
See our EPA pollution monitoring data reports. We list all our facilities' licences, monthly monitoring reports and annual summaries.
Monitoring Greater Sydney's swim sites
There are many places to swim in our natural waterways.
The NSW Government's Beachwatch water quality program monitors water quality for swimming at our harbour and ocean beaches. Sydney Water supports Beachwatch by monitoring the Illawarra beaches.
RiverWatch® is Sydney Water's recreational monitoring and reporting program for the rivers, creeks, lakes and harbour inlets of Greater Sydney's cities and suburbs. It monitors water quality at new and established Urban Plunge® swim sites in the Parramatta River, including at Bayview Park, and helps us identify new swimmable sites.